Alignment change has consequences. But not the same ones for everyone. For a low - level fighter or rogue, the change may have consequences for the character and his or her party, but is not likely to have a major effect on the surrounding world. Alternately, the characters themselves may only be changed on paper. For a paladin or cleric, the character may lose powers and be forced to change class, religion, or even allies. For an Outsider, it is a scandalous thing, and its fellows will seek to resolve the issue before the scandal can grow out of control. When an epic or divine - level being changes alignment, the consequences could be very far reaching. If an overpower changes alignment, the whole setting will likely never be the same again.

This site has an excellent method for those who prefer to use a point system to determine whether an alignment change is justified. However it is a fairly rigid method for enforcing behavior - appropriate alignment changes.

As an alternative to doing things mathematically, the DM can act as the character's boss doing a performance review.

After each epiosode / session, the DM reviews the player characters' behavior and talks to any players whose characters have not been following their alignment; the DM should have at least three examples with justification for why they did not conform to the alignment. If a player wants to keep the old alignment, they should be given time (maybe one gaming session) to correct their character's behavior; if they do not, then the character has been "fired" from their old alignment and must change their alignment accordingly. If they want to change, they should be given a trial period and if they act their new alignment, they can change.

Once a character changes in alignment, after another "trial period", they should be allowed to pursue new classes, religions, etc, as those opportunities become available due to their new alignment.

If a character changes alignment, and then changes back, atonement or other activities such as a quest, gift to charity, etc., may need to be performed before deities that were friendly to the character before their "deviant phase" forgive them.

Some characters who change alignment may become infamous and lose friends, society memberships, etc.; they may have to live in hiding. The alignment demographics of a characters race and culture will determine the severity of the social consequences for going against the grain (e.g., changing one's alignment from the listed alignment for the creature description). Here is the table I use to determine a typical society's attitude towerd such an individual:

Percent of specieswith old alignment

Attide towards nonconformists

40%:

"Whatever dude, we all different."

60%:

"Yes, he is a bit eccentric. Maybe best to just avoid him."

80%:

"Weirdo, outcast, not someone it is acceptable for decent people to be seen associating with."

95%:

"traitor, rebel, extremist, enemy"

99%:

"abomination, should be killed on sight - or maybe under a spell?"

You might want to allow for adjustment up or down one level depending on the exact circumstances, species, local culture, etc., or a roll of the dice.

Given a setting and an NPC, what are the chances an encounter with the player characters might cause them to change alignment? Likewise, when creating an NPC, does their background include one or more alignment changes? In some cases, a plot critical NPCs' alignment is defined by the plot, but in other cases, the DM can afford to be flexible. Here are some ideas on how to decide how easily an NPC might be led to change.

Good is a more internal thing; good restrains itself, always pausing to think of others; evil gives in to temptation, seduces others into its easier, more sensual ways. Many beings start off good, but fall, and it is often easier to send a Paladin in to cauterize the infection than try to convert the fallen back. Under this system, the hack - and - slash style of roleplay is morally justified; as is the good - aligned emperor who orders the arrest of a party for agreeing to meet with the chieftain of a tribe of pirates who raided and pillaged the capitol.

Since most evil beings are fallen, most souls are both inherently evil and inherently good. The good part longs for redemption, and thus with sufficient effort, many evil beings will reform. Under this system, it is not as justifiable for good characters to go around randomly destroying orc villages. It is more justifiable to use diplomacy and subterfuge to avoid killing.

Chaos flows like water, shifting in all things, but Law is rigid and can only convert to Chaos under the rarest circumstances. The forces of Chaos breed without regard to control and thus start out with more, but their children often drift from their parent's beliefs, while the lawful cultivate stubbornness and a love of tradition in their children.

Lawful creatures resist change, but under the right circumstances they will fall astray like shards of broken glass. Lawful creatures thus depart from their own ways more suddenly and completely, where as Chaotic creatures drift about, taking their time to change. It is more difficult for formerly lawful creatures to return to their old ways; formerly chaotic creatures are more able to find new places in chaotic societies if they flip, then flop back.

The alignments are in active and sometimes desperate competition and are trying different strategies in different ways. Thus the alignment demographics and ease of changing alignment will vary from race to race and place to place as religions, factions, etc., vie for dominance.

"Within a given category, creatures with challenge ratings in the middle are more likely to change alignment."

The highest - CR characters rarely change alignment. This is probably more true for the bad guys than for the party's allies, because the author must do what the readers don't like to keep the story interesting. But why?

first off, there are fewer of them, so we're starting out with less to change.

third, most of them have been alive for a long time to reach their current level. Enough time to have considered changing alignment and rejected it many times over.

the real reason, however, is that as the character's most powerful potential foes or allies, the environment would change if they changed. As a result, a wise villian recognizes that forces will try to restore the balance and the powerful face greater penalties for change.